In Cthulhu Dice, players take on the roles of dueling Cthulhu cultists.
Each player starts with three sanity points (represented by glass
beads), and the objective is to be the last player with sanity
remaining. If everyone goes insane at once, Cthulhu (represented by a
"pot" in the middle of the table) wins. Gameplay is simple – the
current player chooses another player as a target, rolls the die, and
resolves the effect of the roll. The targeted player then gets a
retaliatory roll of his or her own. Repeat as needed. Depending on the
symbol that comes up on each roll, players may end up stealing sanity
points from one another, gaining points from Cthulhu, or (in the case of
the dreaded Cthulhu symbol) forcing every player in the game to lose
sanity.

This is definitely not Steve Jackson's best game design by any means –
in fact, I'm awfully tempted to describe it as "advanced dreidel."
Sure, the dreidel has been replaced with a twelve-sided die and the
coins with sanity counters, but the gameplay is pretty much the same,
apart from a slightly greater degree of player interaction. I'm not a
big fan of games of almost pure luck, and, minor strategic elements
aside, this falls squarely into that category.

As you can imagine,
while there is a little bit of strategy in choosing who to target for
your roll, the game is largely a random and chaotic experience. It gets
worse if you add more players – the larger the group, the more likely
that some players will lose all of their sanity to Cthulhu before they
even get a turn. Before claiming to be playable by "2+ players," the
game should probably have been given some better compensatory mechanism
(like variable starting sanity) for larger groups.

Conclusions
Given the very reasonable price point, the quality of the components,
and the brevity of the game itself, this does have its place as a
portable and easy-to-play filler game. However, that doesn't make it a
great game, and you're probably better off coming up with creative use
for the bits than you are trying to play it as-is. There are six
different color combinations of Cthulhu dice, so Cthulhu enthusiasts may
want to pick up a couple of their favorites. There's got to be some
devious way you can utilize these in a Call of Cthulhu campaign!